iwyu: Cleanup include headers

Triggered iwyu and add/remove used headers.

Change-Id: Iadbdb459563b3c89baf2d56f90a540342d020cd5
Signed-off-by: Willy Tu <wltu@google.com>
diff --git a/subprojects/nemora-postd/nemorad.cpp b/subprojects/nemora-postd/nemorad.cpp
index 0ad8010..0531323 100644
--- a/subprojects/nemora-postd/nemorad.cpp
+++ b/subprojects/nemora-postd/nemorad.cpp
@@ -24,6 +24,7 @@
 
 #include <csignal>
 #include <cstdint>
+#include <iostream>
 #include <regex>
 #include <string>
 #include <thread>
diff --git a/subprojects/nemora-postd/src/host_manager.cpp b/subprojects/nemora-postd/src/host_manager.cpp
index b771146..f690389 100644
--- a/subprojects/nemora-postd/src/host_manager.cpp
+++ b/subprojects/nemora-postd/src/host_manager.cpp
@@ -19,7 +19,6 @@
 #include <sdbusplus/message.hpp>
 
 #include <format>
-#include <functional>
 #include <variant>
 
 using phosphor::logging::level;
diff --git a/subprojects/nemora-postd/src/nemora.cpp b/subprojects/nemora-postd/src/nemora.cpp
index f958b01..403d766 100644
--- a/subprojects/nemora-postd/src/nemora.cpp
+++ b/subprojects/nemora-postd/src/nemora.cpp
@@ -26,8 +26,6 @@
 
 #include <cstdint>
 #include <cstring>
-#include <functional>
-#include <iostream>
 #include <variant>
 
 using phosphor::logging::level;